Worth fitting RIFA suppressor?

[mikmas]

I am currently using my Quad 405-2 independently of a Quad pre-amp with power 'pass-through' and switch facility.

Only problem I am encountering is an occasional nasty spike in the speakers at switch on.

I am considering fitting a RIFA suppressor (as used in the 33 and 34 pre's) across the 405-2 power switch.

My questions are:
1. will it make a difference?
2. is it safe?
3. should it go after or before the switch?

[Barry]

It's normal for there to be a dull thud/thump through the speakers at switch on. I assume the preamp is switched on before the power amp, otherwise there will be a nasty click/bang when you switch on the power amp.

Otherwise, I can't see any harm in fitting a RIFA suppressor (or two, as the switch is a double pole device) across the switch. Just make sure it has a sufficiently high rating.

[karma67]

I get that, I just make sure the volumes off before start up.

[mikmas]

It's normal for there to be a dull thud/thump through the speakers at switch on. I assume the preamp is switched on before the power amp, otherwise there will be a nasty click/bang when you switch on the power amp.

Otherwise, I can't see any harm in fitting a RIFA suppressor (or two, as the switch is a double pole device) across the switch. Just make sure it has a sufficiently high rating.

Thanks Barry ... and yes, pre is always 'first on and last off'

Not always a 'dull thump' unfortunately, occasionally a definite 'crack' that makes me jump
The RIFA I have is the same that's fitted to the 33 and 34 pre's as supplied by Dada:

http://www.dadaelectronics.eu/shop/q...100r-evox-rifa


I would fit it as set up on the 34 ... viz:

[Yomanze]

I tend to switch to an unused input on my pre before powering up or down. Stops the big thumps or “whoomphs”.

[Barry]

Thanks Barry ... and yes, pre is always 'first on and last off'

Not always a 'dull thump' unfortunately, occasionally a definite 'crack' that makes me jump
The RIFA I have is the same that's fitted to the 33 and 34 pre's as supplied by Dada:

http://www.dadaelectronics.eu/shop/q...100r-evox-rifa

I would fit it as set up on the 34 ... viz:

The RIFA device looks OK, but I think it should be fitted across both the switch contacts (hence you will need two of them), and not between the live and the neutral leads.

[mikmas]

The RIFA device looks OK, but I think it should be fitted across both the switch contacts (hence you will need two of them), and not between the live and the neutral leads.

I see .... sort of, but just to confirm.

I was going from how Quad apply it in the 34 schematic:


... but what you are suggesting would be more like this:



What would be the particular advantage with this alternative (if I got it right) ?

[Barry]

The latter arrangement is what I had in mind, and is what is used in the Quad 22 preamp. The RIFA devices are spark supressors and prevent clicks occurring when the switch is opened.

I can't recall the arrangement used in the Quad 33 preamp, but I will check and get back to you.

If Quad use the above arrangement as shown in their 34 preamp, then it ought to work for the 405. What speakers are you using? I have used a Quad 405 into Quad 57 ESLs and only experienced a dull thump on switch on, nothing more and certainly not a 'bang'.

[mikmas]

The latter arrangement is what I had in mind, and is what is used in the Quad 22 preamp. The RIFA devices are spark supressors and prevent clicks occurring when the switch is opened.

I can't recall the arrangement used in the Quad 33 preamp, but I will check and get back to you.

Thank you for the confirmation Barry.

The 33 is the same set up as the 34; I have the schematics for both - so no worries on that score
Will give both methods some thought.

[mikmas]

If Quad use the above arrangement as shown in their 34 preamp, then it ought to work for the 405. What speakers are you using? I have used a Quad 405 into Quad 57 ESLs and only experienced a dull thump on switch on, nothing more and certainly not a 'bang'.

Quad 22L or alternatively Quad Lite.

The noise occurs with both (although is really very occasional) and is more a sharp crack than a bang or thump. I take that to be dependent on where in the AC cycle it is switched on